The present novel concept broadly relates to the art of fluid suspension devices and, more particularly, to an air spring assembly with a non-threaded interface adapted to connect or otherwise attach an associated component, such as an air line or a sensor.
The subject connector fitting finds particular application and use in association with air springs and vehicle suspension systems, and will be described herein with specific reference thereto. However, it is to be understood that the subject novel concept is amenable to broad use and, as such, is equally applicable in other suitable environments. Accordingly, it will be understood that the present novel concept is not intended to be limited to the uses and/or applications described herein, which are merely exemplary.
Most known compression fittings for fluid lines, as well as other multi-piece connectors of similar types, can be used to secure an air supply line to an air spring. In such arrangements, an end member of the air spring is normally provided with a threaded passage that provides communication with the spring chamber of the air spring. The compression fitting is then threaded into the passage. Once the fitting has been installed, the air line is connected thereto in a traditional manner. While such fittings tend to provide a relatively robust connection between the air line and the air spring, numerous problems nonetheless exist with these types of connections. For example, the threaded connection with the end member of the air spring can to provide a leak path, which undesirably increases air consumption and decreases system efficiency.
Additionally, compression-type fittings are often difficult and time consuming to install, especially in areas of limited clearance, such as between structural members and/or body panels of a vehicle, for example. Though the body of such a fitting can often be installed ahead of time, numerous other parts of the compression fitting and fluid line need to be arranged and manipulated after the air spring has been installed on the vehicle. This undesirably increases the time and effort required to install or replace an air spring of a vehicle suspension system.
What's more, the air line is usually secured in a fixed position on a compression fitting. That is, the air line is normally not permitted to move or rotate relative to the connector or air spring. Thus, the air line and/or fitting can become undesirably stressed due to the movements of the vehicle body. Additionally, such an arrangement could result in the air line being positioned against or otherwise contacting a structural member or the object. As a result, chaffing, abrasion or other degradation of the air line could occur. These conditions are disadvantageous and can lead to premature maintenance, repair and/or replacement of the air line and/or connector fitting.
Furthermore, the nature of the fitting and the need for the fitting body and other components to be accessible for the proper installation of the air line, requires that the majority of the fitting project or otherwise extend outwardly from the air spring. As a result, a certain minimum amount of peripheral clearance is needed for wrenches or other tools used during the connection of the air line. This external mounting arrangement also mandates that the fitting have a certain minimum length, which typically significantly increases the overall height of the air spring and fitting assembly. The disadvantage of the extra height is further increased where the end member of the air spring has an outwardly projecting boss into which the fitting body is threaded.
As an alternative to compression and other multi-piece fittings, so called “push-to-connect” (PTC) fittings have been developed and have been used in air spring applications. Generally, these types of connections provide for easier connection of the air line relative to compression fittings, and PTC fittings also typically permit the air line to rotate or swivel, which can reduce the stress on the air line and the fitting. Though PTC fittings have improved certain aspects of the air spring/air line connection, numerous disadvantages remain with the use of these types of connector fittings.
One example of such a disadvantage is that PTC fittings used heretofore have only minimally reduced to overall length of the fitting, if any reduction at all has been achieved. Thus, the portion of the fitting extending from the threaded connection undesirably increases the overall height dimension of the air spring. As a result, the foregoing clearance and other issues associated with this increased overall height remain unresolved by known PTC fittings.
A further disadvantage is that such PTC fittings remain threadably installed on the exterior of the end member of the air spring. Therefore, a threaded passage is normally required on the end member of the air spring and the resulting leakage issues, discussed above, remain unresolved. Additionally, loads from tension and movements of the air line, impacts from road debris and changing temperatures can all act to degrade the integrity of the threaded connection of both PTC and compression fittings. This is at least partly due to the installation of the fitting along the exterior of the air spring.
Regardless of the type, kind or configuration of threaded fitting that may be used, the provision and use of threads to connect an air line or sensor will have numerous disadvantages associated with such use. One disadvantage is simply the costs associated with machining the threads on the air spring part or parts. That is, substantially tight tolerances are normally maintained on the threaded features and, typically, higher costs are associated with holding tighter tolerances. For example, where the threaded part is to be plated or coated, such as for corrosion resistance, dimensional allowances should be provided on the threads to accommodate the plating or coating buildup that is to be later applied.
Furthermore, threaded connections can result in the deflection of parts or features which, in turn, can cause assembly or other problems. For example, air springs commonly use mounting studs projecting from a top or bead plate to secure the air spring to an associated structural member. One type of mounting stud is commonly referred to as a combination stud or fitting, and includes a central passage used to communicate with the spring chamber of the air spring. Typically, these so called combination fittings include both internal and external threads. A threaded connector fitting is typically secured along the threaded passage to connect the air line. To form a suitable fluid-tight connection, however, tapered threads, such as pipe threads, are normally used. As the fitting is tightened into the internal threads of the combination fitting, the same becomes outwardly deflected. As a result, the external threads become oversized, which can undesirably cause assembly problems.